This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Until today it is unclear, whether and how DNA damage, - which alters the integrity of genomic DNA -, influences stem cells on protein level, e.g. whether stem cell-maintaining factors are directly regulated in response to DNA damage. We apply MudPIT to solve this question with mass spectrometry-based protein identification and quantification.